Spaying your dog helps prevent uterine infections and breast tumors, which are malignant or cancerous in about 50 percent of dogs and 90 percent of cats. Spaying your pet before her first heat offers the best protection from these diseases. Neutering your male companion prevents testicular cancer and some prostate problems.
Neutering will often decrease or eliminate other objectionable male dog behaviors, such as mounting furniture and family members. Male dogs and cats will cease roaming to find a mate because the hormonal urge to do so has been removed. Neutered animals are not sexually frustrated.